The anterior cruciate ligament (ACL) spans the knee joint and attaches to the upper bone, the femur, and the lower bone, the tibia, to maintain smooth movement between their adjacent surfaces as the knee is bent. The ACL is known to tear during sporting accidents, thereby requiring replacement with a graft.
Orthopedic surgeons who conduct ACL repair, which includes replacement surgery, are continuously in search of methods and devices to improve the outcome of the surgery. A common problem in conventional ACL repair surgery is the lack of adjustability of the tension placed upon ligament graft, which results in poor graft performance. It is desirable, during installation of the ACL graft to keep the graft from becoming unduly twisted, since twisting of the graft causes it to become unduly stressed and thereby more prone to failure.
Conventional surgical techniques for repairing the ACL require drilling a bore through the tibia, across the knee jont and into the upper bone, the femur, and passing a ligament or tendon graft up the bore and fastening one end of the graft to the upper bone, the femur, and, attaching the opposite end of the graft to the Tibia. Typically, bone screws and bone staples are placed through the end of the ligament graft that protrudes from the bore, fastening it to the Tibia. Such fasteners are almost never removed and replaced during surgery to adjust ligament tension. Hence, if, during surgery, the replacement ligament in perceived to be loose, allowing excessive play between the upper bone, the femur, and the lower bone, the tibia, it is often left this way, leading to discomfort and pain in the knee postoperatively.
In methods where the ligament graft is attached to a femoral screw prior to surgery, with the attachment being where the ligament graft passes through a ring at the end of the screw, the screw is rotated into the femur and the ligament graft can twist and weaken during insertion.
When a pre-formed ligament or tendon is affixed to the femur with with prior art devices, the tissue is generally affixed to the surface of a bone with a screw with a ring at the end, a button with a loop of material to which the graft is attached, or other attachment means. Commercial embodiments of such devices that allow the graft to be preformed and attached to a ringed screw that screws into the femur, include the ACL Anchor System, manufactured by T.A.G. Medical Products of Israel. Embodiments of buttons and wing-like pieces that rest on the upper surface of the femur and are attached to a graft that is suppended below by a ring or loop, include, the ENDO-BUTTON™ by Smith and Nephew Endoscopy of Andover Mass., and the COBRA LFD™ by Atlantech Medical Devices of Harrogate, England.
In this last category of fastener, the button or wing-like device is rotated from the vertical position when it is being passed through the bore, to the horizontal position so that it sits on the surface of the femur, by marionette-like strings that are manipulated from above the femoral surface. The manipulation of these marionette-like strings requires that the strings are passed through the femoral bore and up through the muscle and skin above the femoral surface prior to installation of the device and then used to pull the device up through the bore and rotate it into position. This necessitates considerable finesse and requires additional incisions in the skin for the exit of the strings. For example, an incision would be required in the thigh and upper shin of a leg in order to install prior art devices. As the wing or button is not rotated via a solid shaft, but via strings, the surgeon cannot easily judge the exact position of the button or wing vis-à-vis the bone. With such devices, the button or wing, rather than resting on the bone, rests on soft tissue above the bone. As the button or wing works its way through the soft tissue, the graft becomes loose. Additionally, the tissue below the wing or button can necrose, resulting in less than optimal muscle function.
None of these devices include a flip-wing tissue retainer with an installation method as described herein. A need remains for a surgical method and device that overcomes the disadvantages inherent in conventional surgical methods of tissue repair.